KR102280644B1 - Method for eliminating pollutant from solution - Google Patents

Abstract

The present invention relates to a method for removing an amine-based compound present in a waste liquid generated during coke oven gas treatment, and more particularly, to a method for removing an amine-based compound comprising: providing a solution to be treated comprising an amine-based compound and a heat-stable salt; and adding ozone and activated carbon to the solution to be treated.

Description

Method for eliminating pollutant from solution

The present invention relates to a method for removing contaminants from a solution containing an amine-based compound and a heat-stable salt.

The gas (coke oven gas, COG) generated during coke production is treated by using the acid gas absorption liquid to contain the acid gas in the gas, then regenerating the absorption liquid in which the acid gas is collected and reusing it in the process. As the absorbent used at this time, various absorbent liquids, such as ammonia water, are used, and the ammonia is removed through a distillation process together with the wastewater generated in the coke manufacturing process, and then finally treated through a biological water treatment process before being discharged.

In particular, Patent Registration No. 1829225 discloses a method of using methyldiethanolamine (MDEA) to remove hydrogen sulfide and ammonia contained in COG. In the case of treating these components through biological treatment, research on a method for effective treatment is still insufficient.

On the other hand, during the COG treatment process using MDEA, heat stable salt (HSS), which may be generated by the decomposition of MDEA, the component supplied from the COG, the component supplied from the COG, and the reaction of MDEA, has the acid gas capture performance of MDEA and causes various problems such as foaming and corrosiveness. Therefore, in order to remove HSS in the process as described above, a method such as a thermal reclaimer, an electrodialysis reclaimer (ED), an ion exchange reclaimer (IX) is used. are doing

However, since the waste liquid generated in the reclaimer process contains MDEA and a high concentration of HSS, a method for treating it is required.

The present invention provides a method for effectively treating amine-based compounds and heat-stable salts in waste liquids generated in an acid gas collection process using amines.

The present invention provides a solution to be treated comprising an amine-based compound and a heat-stable salt; and adding ozone and activated carbon to the solution to be treated.

The present invention can improve the treatment rate of amine compounds and heat-stable salts in waste liquids generated in the COG treatment process using amine compounds, and furthermore, can effectively remove low-concentration contaminants, thereby reducing the amount of ozone or hydrogen peroxide can do it

1 shows a method of injecting ozone and hydrogen peroxide together with a solution to be treated including an amine-based compound and a heat-stable salt into a container in which an activated carbon bed is installed as an embodiment of a method for removing contaminants from a solution of the present invention.
2 is an embodiment of a method of removing contaminants from a solution of the present invention, showing a method of injecting ozone and hydrogen peroxide together with a solution to be treated containing an amine-based compound and a heat-stable salt into a container in which activated carbon particles are injected. .
3 shows a case in which ozone and activated carbon are used according to an embodiment of the present invention (Example 1), when only ozone is used and activated carbon is not used (Comparative Example 1), and when ozone and activated carbon are not used (Comparative Example) It shows the degree to which the amine-based compound of 2) is removed.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The waste liquid generated in the acid gas treatment process of the coke oven gas contains various contaminants, and among them, the waste liquid contains an amine-based compound and a heat-stable salt used to remove the acid gas. In this case, the heat-stable salt may be a material produced by combining the amine-based compound used in the treatment process for removing the acid gas in the coke oven gas and various contaminants present in the process.

Heat stable salt (HSS) generated among the contaminants may be treated using a reclaimer system.

However, during the process of removing the heat-stable salt using the reclaimer, the generated waste solution contains a high concentration of the heat-stable salt, and the coke oven gas still contains the amine-based compound used in the acid gas treatment process.

Accordingly, the present invention provides a method for removing the amine-based compound from a solution to be treated containing the amine-based compound and a heat-stable salt.

In detail, the present invention provides a solution to be treated comprising an amine-based compound and a heat-stable salt; and adding ozone and activated carbon to the solution to be treated.

In this case, the solution to be treated may be a solution generated by treating waste liquid generated in the acid gas treatment process among coke oven gas with a reclaimer system, but if it contains an amine compound and a heat-stable salt, it is not limited thereto , for example, may be igneous wastewater containing hardly degradable pollutants.

Further, the reclaimer system is, as described above, a thermal reclaimer, an electrodialysis reclaimer, an ion exchange reclaimer or a capacitive desalination reclaimer ( capacitive deionization reclaimer) may be used, but the reclaimer system used may vary depending on the type of the amine-based compound. For example, an amine-based compound with a low boiling point (eg, MEA) can be removed by using a thermal reclaimer, and an amine-based compound having a high boiling point and decomposition at high temperature (eg, For example, MDEA) may use an electrodialysis reclaimer or an ion exchange reclaimer.

On the other hand, the amine-based compound may be an ethanolamine, for example, methyldiethanolamine (methyldiethanolamine, MDEA), monoethanolamine (monoethanolamine, MEA), diethanolamine (diethanolamine, DEA) and triethanolamine (triethanolamine, TEA) may be at least one selected from the group consisting of, but is not limited thereto.

Furthermore, in the step of adding ozone and activated carbon, an amine-based compound may be removed by further adding hydrogen peroxide in addition to ozone and activated carbon. When ozone and hydrogen peroxide are used at the same time to remove the amine compound, the decomposition rate of the amine compound is improved by three times.

For example, ozone and hydrogen peroxide may be first injected into the solution to be treated, and then activated carbon may be injected, or ozone, activated carbon, and hydrogen peroxide may be simultaneously injected into the solution to be treated. Accordingly, in the step of adding ozone and activated carbon, hydrogen peroxide may be additionally added.

The activated carbon may use at least one form selected from the group consisting of powdery, granular and pellet, but is not limited thereto, and a form capable of adsorbing organic matter without distinguishing raw materials such as palm-based and coal-based activated carbon. It is possible with activated carbon of For example, a bed-type activated carbon fixed to an amine-based compound processing apparatus is used (FIG. 1), or granular activated carbon (GAC) or powdered activated carbon is mixed with the solution to be treated. It can be used in a mixed form (FIG. 2).

The activated carbon can increase the removal rate of the amine-based compound, and when the amine-based compound is present at a low concentration, the decomposition rate slows down due to mass transfer of radicals formed by ozone or a combination of ozone and hydrogen peroxide. .

When activated carbon is injected, a low concentration of an amine-based compound is adsorbed to the activated carbon, thereby solving the limitation of mass transfer due to the low concentration, and the amine-based compound can be removed by efficiently using radicals generated from ozone or ozone/hydrogen peroxide.

In the step of adding ozone and activated carbon, the ozone may be added in an amount of 0.1 to 1.0 parts by weight, preferably 0.1 to 0.5 parts by weight, per 1 part by weight of the amine-based compound. When the amount added is less than 0.1 parts by weight, sufficient decomposition of the amine-based compound is not performed well, and when added in an amount of 1.0 parts by weight or more, unreacted ozone may be generated.

Further, in the step of adding ozone and activated carbon, 0.05 parts by weight of the activated carbon per 1 part by weight of the amine-based compound may be added in an amount of 5.0 parts by weight of the inner periphery, preferably 0.1 to 2.0 parts by weight, and the amount of the activated carbon added is 0.05 parts by weight If the amount is less than, the activated carbon is saturated with the amine-based compound and additional adsorption does not occur, so that when the amine-based compound is continuously supplied, a problem of lowering treatment efficiency may occur, and if it is added in excess of 5.0 parts by weight, the activated carbon may contain an amine-based compound By adsorbing most of the compounds, there may be a problem in that the decomposition rate of the amine-based compound by ozone may be inhibited.

On the other hand, as described above, the waste liquid discharged from the reclaimer system contains a high concentration of heat-stable salt, and still contains an amine-based compound, and in particular, in the case of heat-stable salt, bioavailability is high, so biological treatment Although it can be decomposed through the process, in the case of amine compounds, the bioavailability is low when present in solution, so the decomposition rate is slow, and when finally discharged, the chemical oxygen demand (COD) and total nitrogen (Total- Nitrogen, TN) concentration can be increased.

Accordingly, activated carbon and ozone or activated carbon, ozone and hydrogen peroxide are injected into the solution to be treated to selectively remove amine-based compounds and then heat-stable salts can be removed. This is because the heat stable salt can also be removed by ozone or ozone and hydrogen peroxide. For example, it may include the step of performing a biological treatment process including an anaerobic tank, anaerobic tank and aerobic tank subsequently to the solution that has been subjected to the step of adding ozone and activated carbon.

The biological treatment process may use a conventionally used biological treatment system, and any biological treatment system used in the art may be used without limitation, for example, an anaerobic tank, anaerobic tank, aerobic tank, anaerobic tank and aerobic tank connected in order Treatment process equipment may be used to remove thermostable salts.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

10 g of MDEA as an amine compound and 10 to 20 g of formic acid as a heat stable salt (HSS) were injected into deionized water to prepare 800 mL of a solution to be treated containing the amine compound and heat stable salt.

Thereafter, a process for removing MDEA from the solution to be treated was performed as follows.

Example 1

The content of MDEA in the solution over time was measured when ozone was supplied at a level of 60 mg per minute and particulate activated carbon was injected at a concentration of 0.8 g to 800 mL of the solution to be treated containing amine.

Comparative Example 1

The content of MDEA in the solution over time was measured when ozone was supplied at a level of 60 mg per minute to 800 mL of the solution to be treated containing the amine.

Comparative Example 2

The content of MDEA in the solution over time was measured when air was supplied at a level of 1 L per minute for 800 mL of the amine-containing solution to be treated.

Real-time amine compound concentration measurement result

During the reaction in Example 1 and Comparative Examples 1 and 2, the results of measuring the MDEA content in the solution for each time are shown in FIG. 3 .

As a result, it was confirmed that the MDEA content measured in Example 1 and Comparative Example 1 after completion of the reaction was 12.2 g and 13.9 g, respectively, and the MDEA content measured in Comparative Example 2 was 21.1 g.

In particular, the MDEA contents in Example 1 and Comparative Example 1 in the initial 10 minutes of the reaction were 15.0 g and 18.7 g, respectively, and the amount of MDEA removal in Example 1 using activated carbon was remarkably excellent. From this, it was confirmed that a large amount of MDEA could be removed with the same amount of ozone when activated carbon was used.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (9)

treating the waste liquid generated in the acid gas treatment process in the coke oven gas with a reclaimer system;
providing a solution containing an amine-based compound and a heat-stable salt generated by treatment with the reclaimer system as a solution to be treated;
adding ozone and activated carbon to the solution to be treated; and
comprising performing a biological treatment process comprising an anaerobic tank, an anaerobic tank and an aerobic tank,
A method of removing contaminants from a solution.
delete According to claim 1,
The reclaimer system is a thermal reclaimer, an electrodialysis reclaimer, an ion exchange reclaimer or a capacitive deionization reclaimer. How to remove contaminants from
According to claim 1,
The amine-based compound is at least one selected from the group consisting of methyldiethanolamine (methyldiethanolamine, MDEA), monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA), A method of removing contaminants from a solution.
According to claim 1,
The method of removing contaminants from a solution, wherein the step of adding ozone and activated carbon further adds hydrogen peroxide.
According to claim 1,
The method of claim 1, wherein the activated carbon is in at least one form selected from the group consisting of powdered, granular and pellets.
According to claim 1,
A method of removing contaminants from a solution, wherein the ozone is added in an amount of 0.1 to 1.0 parts by weight per 1 part by weight of the amine compound.
According to claim 1,
A method of removing contaminants from a solution, wherein the activated carbon is added in an amount of 0.05 to 5.0 parts by weight per 1 part by weight of the amine compound.
delete

Images